Malignant transformation of oral leukoplakia: Systematic review and meta-analysis of the last 5 years.

Oral leukoplakia (OL) is the most frequently encountered oral potentially malignant disorder. The aims of this systematic review are to estimate the overall malignant transformation of OL and to assess the risk factors associated with malignant transformation of OL published in the last 5 years (2015-2020). We performed a bibliographic search in PubMed, Scopus, Web of Science, Embase, and Cochrane databases with keywords "oral leukoplakia", "oral cancer", "oral carcinoma" and "oral squamous cell carcinoma". Meta-analysis was conducted using a random-effects model. Twenty-four studies were selected, that reported a total of 16,604 patients. Malignant transformation proportion varied between 1.1% and 40.8%. Female gender, non-homogeneous clinical type, and presence of epithelial dysplasia were significantly related to MT. Other risk factors previously suggested did not show significant results. The pooled proportion of malignant transformation MT was 9.8% (95% CI: 7.9-11.7). It is necessary to continue to conduct well-designed prospective clinicopathological studies on OL, using a uniform definition for OL to reduce the risk of bias for evaluating various factors associated with the MT.

Aguirre-Urizar JM ，Lafuente-Ibáñez de Mendoza I ，Warnakulasuriya S 《-》

Malignant transformation rate of oral leukoplakia in the past 20 years: A systematic review and meta-analysis.

This meta-analysis aimed to assess the rate of malignant transformation (MT) of oral leukoplakia (OL) and to study potential risk factors for the MT of OL into oral squamous cell carcinoma (OSCC). We performed a bibliographic search on nine electronic databases, including PubMed, MEDLINE, and Wanfang Data, for data on the MT rate of OL. Possible risk factors were calculated using Comprehensive Meta-Analysis and Open Meta [Analyst] software. The pooled proportion of OL MT for the total population described in the 26 selected studies was 7.20% (95% confidence interval: 5.40-9.10%). Nonhomogeneous type lesions, higher grades of dysplasia, the location of the lesion (tongue and multifocal), and female sex had significant effects on the MT of OL. OL tended to develop into OSCC (7.2%), and those with significant MT risk factors should be subjected to regular follow-up and observation. However, we require large-scale prospective studies to validate these results, together with unified clinicopathological diagnostic criteria, standardized risk factor recording/assessment methods, and long-term follow-up guidelines.

Guan JY ，Luo YH ，Lin YY ，Wu ZY ，Ye JY ，Xie SM ，Li J ... -  《-》

Annual malignant transformation rate of oral leukoplakia remains consistent: A long-term follow-up study.

Numerous clinical and histopathological characteristics have been associated with malignant transformation (MT) of oral leukoplakia (OL), including classic and differentiated epithelial dysplasia, but MT predictions remain suboptimal. The objective of this study was to determine the annual MT rate of OL and to identify clinicopathological risk factors associated with MT. 170 patients with OL were included in this retrospective cohort study, 117 females and 53 males. Follow-up ranged from 12 to 219 months (median 54). The analyzed variables included age, gender, smoking habits, clinical presentation, subsite, size and treatment. In a subgroup of 140 patients, histopathological diagnoses were reviewed with regard to the presence of dysplasia, discerning both classic dysplasia and differentiated dysplasia. MT occurred in 23% of the patients, resulting in an annual MT rate of 4.9% (95% CI: 3.5 - 6.6) which remained consistent. High-risk subsite (tongue and floor of mouth) was the only clinical predictor for MT (Hazard Ratio = 2.7, 95% CI: 1.3 - 5.5, p = 0.007). In 140 patients, classic dysplasia (Hazard Ratio = 7.2, 95% CI: 1.6 - 33.1, p = 0.012) and differentiated dysplasia (Hazard Ratio = 6.6, 95% CI: 1.2 - 25.4, p = 0.026) were predictors for MT. Binary grading between dysplasia and no dysplasia was significant for predicting MT (Hazard Ratio = 6.4, 95% CI: 1.5 - 27.5, p = 0.013). Since annual MT rate of OL remains stable during follow-up, regular long-term or even life-long follow-up is advocated. Specific oral subsites and epithelial dysplasia are predictors for MT of OL.

Evren I ，Brouns ER ，Wils LJ ，Poell JB ，Peeters CFW ，Brakenhoff RH ，Bloemena E ，de Visscher JGAM ... -  《-》

Critical update, systematic review, and meta-analysis of oral erythroplakia as an oral potentially malignant disorder.

Oral erythroplakia has been classically considered as the potentially malignant disorder with the highest rate of malignant development into squamous cell carcinoma. This critical systematic review and meta-analysis aim to estimate the malignant development rate of oral erythroplakia and identify the associated risk factors. We performed a bibliographic search in PubMed, Scopus, Web of Science, Embase, and LILACS, with keywords "erythroplakia," "erythroplasia," "malignant transformation," "malignant development," "malignization," "carcinogenesis," "oral cancer," "oral squamous cell carcinoma," "mouth neoplasm," and "prognosis." Meta-analysis was conducted using a random-effects model. Ten observational studies with 441 patients met the inclusion criteria, whose mean malignant development rate was 12.7% and with a mean follow-up period of patients of 6.66 years. In the initial biopsy, 42.8% of oral erythroplakia were already squamous cell carcinoma. The buccal mucosa was the most frequent location of oral erythroplakia, but the floor of the mouth was the most common site of malignant development. All patients who underwent malignant development showed epithelial dysplasia on the initial diagnostic biopsy. Overall malignant development rate of OE in the meta-analysis was 19.9%. We could not associate any specific clinicopathological feature with the malignant development. The presence of epithelial dysplasia in the initial biopsy remains the worst prognostic factor. Further observational studies on OE are needed, with well-established diagnostic criteria and good clinical follow-up, in order to identify the true risk of malignant development of oral erythroplakia and the related risk factors.

Lorenzo-Pouso AI ，Lafuente-Ibáñez de Mendoza I ，Pérez-Sayáns M ，Pérez-Jardón A ，Chamorro-Petronacci CM ，Blanco-Carrión A ，Aguirre-Urízar JM ... -  《-》

Malignant transformation of oral leukoplakia treated with carbon dioxide laser: a meta-analysis.

Dong Y ，Chen Y ，Tao Y ，Hao Y ，Jiang L ，Dan H ，Zeng X ，Chen Q ，Zhou Y ... -  《-》